diff --git a/README.md b/README.md
index 8d7e8aee..85fb4975 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,103 @@
-# java-baseball-precourse
\ No newline at end of file
+# 숫자 야구 게임
+
+## 📌 프로젝트 소개
+1~9 사이의 서로 다른 숫자 3개로 구성된 정답을 컴퓨터가 생성하고, 사용자는 숫자를 입력하여 스트라이크/볼 힌트를 통해 정답을 맞히는 콘솔 게임입니다.  
+정답(3 스트라이크)을 맞히면 게임이 종료되며, 사용자는 게임을 재시작(1)하거나 완전히 종료(2)할 수 있습니다.
+
+---
+
+## ✅ 기능 목록
+
+### 게임 흐름
+- [x] 게임 시작 시 컴퓨터가 1~9 범위의 서로 다른 숫자 3개를 생성한다.
+- [x] 사용자에게 숫자 입력을 요청하고 입력을 받는다.
+- [x] 입력한 숫자에 대한 스트라이크/볼/낫싱 힌트를 계산하여 출력한다.
+- [x] 3스트라이크가 되면 게임 종료 메시지를 출력한다.
+- [x] 게임 종료 후 `1(재시작)` / `2(종료)` 입력을 받아 처리한다.
+    - [x] 재시작 시 정답 숫자를 새로 생성하여 게임을 다시 진행한다.
+    - [x] 종료를 선택하면 프로그램을 종료한다.
+
+### 입력 검증 / 예외 처리
+- [x] 사용자 입력이 잘못된 경우 `[ERROR]`로 시작하는 에러 메시지를 출력하고 게임을 계속 진행한다.
+- [x] 숫자 입력 검증
+    - [x] 3자리인지 검증한다.
+    - [x] 각 자리가 1~9 범위인지 검증한다. (도메인: `BaseballNumber`)
+    - [x] 3자리 숫자가 서로 다른 수인지 검증한다. (도메인: `BaseballNumbers`)
+- [x] 재시작/종료 입력 검증
+    - [x] 1 또는 2만 허용한다.
+
+---
+
+## 🧱 도메인 모델
+
+### `BaseballNumber`
+- 한 자리 숫자를 의미하는 값 객체(Value Object)
+- 유효 범위: 1~9
+- 생성 시 검증을 수행하여 항상 유효한 상태만 유지
+
+### `BaseballNumbers` (일급 컬렉션)
+- `BaseballNumber` 3개를 보유하는 일급 컬렉션
+- 생성 시 다음 규칙을 검증하여 항상 유효한 상태만 유지
+    - 숫자 개수는 3개
+    - 서로 다른 숫자(중복 없음)
+
+### `Hint`
+- 스트라이크/볼 결과를 표현하는 값 객체
+
+### `BaseballGame`
+- 정답 보유 및 입력과의 비교 결과(`Hint`) 생성
+
+---
+
+## 🧩 패키지 구조(예시)
+
+- `game.baseball.domain`
+    - `BaseballNumber` : 한 자리 숫자(1~9)
+    - `BaseballNumbers` : 3자리 숫자 일급 컬렉션(개수/중복 검증)
+    - `Hint` : 스트라이크/볼 결과 값 객체
+    - `BaseballGame` : 정답 보유 및 힌트 계산
+
+- `game.baseball.application`
+    - `BaseballGameService` : 게임 시작 및 추측 처리(유즈케이스)
+
+- `game.baseball.application.port`
+    - `in` : `BaseballGameUseCase`, `command(GuessCommand, RestartCommand)`
+    - `out` : `GameInputPort`, `GameOutputPort`, `NumberGeneratorPort`
+
+- `game.baseball.adapter`
+    - `in` : `BaseballGameInputView`, `BaseballGameOutputView`, `BaseballGameController`
+    - `out` : `RandomNumberGenerator`, `BaseballPrinter`
+
+- `game`
+    - `Application` : 프로그램 시작점(의존성 조립)
+    - `GameRunner` : 실행 트리거
+
+> 핵심 로직(도메인/애플리케이션)과 UI(System.in/out)를 분리하여, 도메인 로직을 단위 테스트 대상으로 삼습니다.
+
+---
+
+## 🧪 테스트 전략
+- 도메인 로직에 대해 단위 테스트를 작성합니다.
+- UI 로직(System.in/out, Scanner 등)은 테스트 범위에서 제외합니다.
+- JUnit5 + AssertJ를 사용합니다.
+
+---
+
+## ⚙️ 프로그래밍 요구사항 준수
+- indent depth는 2까지만 허용합니다.
+- `else`, `switch/case`를 사용하지 않습니다.
+- Java Stream API를 사용하지 않습니다. (람다는 가능)
+- 메서드는 15라인을 넘지 않도록 분리합니다.
+
+---
+
+## ▶️ 실행 방법(예시)
+- IDE에서 `Application.main()` 실행
+- 또는 Gradle 기반 프로젝트라면:
+    - `./gradlew test`
+    - `./gradlew run`
+
+---
+
+## ✍️ 커밋/진행 방식
+- 기능 구현 전 README에 기능 목록을 작성하고, 기능 단위로 커밋합니다.
diff --git a/src/main/java/Application.java b/src/main/java/Application.java
new file mode 100644
index 00000000..162338ff
--- /dev/null
+++ b/src/main/java/Application.java
@@ -0,0 +1,9 @@
+import game.GameRunner;
+import game.baseball.config.BaseballGameConfig;
+
+public class Application {
+    public static void main(String[] args) {
+        GameRunner gameRunner = new BaseballGameConfig().gameRunner();
+        gameRunner.run();
+    }
+}
diff --git a/src/main/java/game/GamePrinter.java b/src/main/java/game/GamePrinter.java
new file mode 100644
index 00000000..30070c32
--- /dev/null
+++ b/src/main/java/game/GamePrinter.java
@@ -0,0 +1,6 @@
+package game;
+
+public interface GamePrinter {
+    void printStartingMessage();
+    void printEndingMessage();
+}
diff --git a/src/main/java/game/GameRunner.java b/src/main/java/game/GameRunner.java
new file mode 100644
index 00000000..b7abd7da
--- /dev/null
+++ b/src/main/java/game/GameRunner.java
@@ -0,0 +1,17 @@
+package game;
+
+public class GameRunner {
+    private final GamingConsole nowRunningGame;
+    private final GamePrinter nowRunningGamePrinter;
+
+    public GameRunner(GamingConsole nowRunningGame, GamePrinter nowRunningGamePrinter) {
+        this.nowRunningGame = nowRunningGame;
+        this.nowRunningGamePrinter = nowRunningGamePrinter;
+    }
+
+    public void run() {
+        nowRunningGamePrinter.printStartingMessage();
+        nowRunningGame.play();
+        nowRunningGamePrinter.printEndingMessage();
+    }
+}
diff --git a/src/main/java/game/GamingConsole.java b/src/main/java/game/GamingConsole.java
new file mode 100644
index 00000000..0573e40f
--- /dev/null
+++ b/src/main/java/game/GamingConsole.java
@@ -0,0 +1,5 @@
+package game;
+
+public interface GamingConsole {
+    void play();
+}
diff --git a/src/main/java/game/baseball/adapter/RandomNumberGenerator.java b/src/main/java/game/baseball/adapter/RandomNumberGenerator.java
new file mode 100644
index 00000000..4f59f6f9
--- /dev/null
+++ b/src/main/java/game/baseball/adapter/RandomNumberGenerator.java
@@ -0,0 +1,33 @@
+package game.baseball.adapter;
+
+import game.baseball.application.port.out.NumberGeneratorPort;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public class RandomNumberGenerator implements NumberGeneratorPort {
+    private static final int NUMBER_COUNT = 3;
+    private static final int MIN_NUMBER = 1;
+    private static final int MAX_NUMBER = 9;
+    private static final int RANDOM_RANGE = MAX_NUMBER - MIN_NUMBER + 1;
+
+    private final Random random = new Random();
+
+    @Override
+    public List<Integer> generate() {
+        List<Integer> numbers = new ArrayList<>();
+        while (numbers.size() < NUMBER_COUNT) {
+            int candidate = random.nextInt(RANDOM_RANGE) + MIN_NUMBER;
+            addIfAbsent(numbers, candidate);
+        }
+        return numbers;
+    }
+
+    private void addIfAbsent(List<Integer> numbers, int candidate) {
+        if (numbers.contains(candidate)) {
+            return;
+        }
+        numbers.add(candidate);
+    }
+}
diff --git a/src/main/java/game/baseball/adapter/in/BaseballGameController.java b/src/main/java/game/baseball/adapter/in/BaseballGameController.java
new file mode 100644
index 00000000..9a7e4eea
--- /dev/null
+++ b/src/main/java/game/baseball/adapter/in/BaseballGameController.java
@@ -0,0 +1,87 @@
+package game.baseball.adapter.in;
+
+import game.GamingConsole;
+import game.baseball.application.port.in.BaseballGameUseCase;
+import game.baseball.application.port.in.command.GuessCommand;
+import game.baseball.application.port.in.command.RestartCommand;
+import game.baseball.application.port.out.GameInputPort;
+import game.baseball.application.port.out.GameOutputPort;
+import game.baseball.domain.Hint;
+
+public class BaseballGameController implements GamingConsole {
+    private final BaseballGameUseCase useCase;
+    private final GameInputPort inputPort;
+    private final GameOutputPort outputPort;
+
+    public BaseballGameController(
+            BaseballGameUseCase useCase,
+            GameInputPort inputPort,
+            GameOutputPort outputPort
+    ) {
+        this.useCase = useCase;
+        this.inputPort = inputPort;
+        this.outputPort = outputPort;
+    }
+
+    @Override
+    public void play() {
+        while (true) {
+            useCase.startNewGame();
+            playUntilSolved();
+            if (!restartSelected()) {
+                return;
+            }
+        }
+    }
+
+    private void playUntilSolved() {
+        while (true) {
+            Hint hint = readValidHint();
+            outputPort.showResult(hint);
+            if (hint.isSolved()) {
+                outputPort.showGameEnd();
+                return;
+            }
+        }
+    }
+
+    private Hint readValidHint() {
+        while (true) {
+            Hint hint = tryGuessOnce();
+            if (hint != null) {
+                return hint;
+            }
+        }
+    }
+
+    private Hint tryGuessOnce() {
+        try {
+            outputPort.showGuessPrompt();
+            GuessCommand command = inputPort.readGuessCommand();
+            return useCase.guess(command);
+        } catch (IllegalArgumentException e) {
+            outputPort.showError(e.getMessage());
+            return null;
+        }
+    }
+
+    private boolean restartSelected() {
+        while (true) {
+            Boolean restart = tryReadRestartCommand();
+            if (restart != null) {
+                return restart;
+            }
+        }
+    }
+
+    private Boolean tryReadRestartCommand() {
+        try {
+            outputPort.showRestartPrompt();
+            RestartCommand command = inputPort.readRestartCommand();
+            return command.restart();
+        } catch (IllegalArgumentException e) {
+            outputPort.showError(e.getMessage());
+            return null;
+        }
+    }
+}
diff --git a/src/main/java/game/baseball/adapter/in/BaseballGameInputView.java b/src/main/java/game/baseball/adapter/in/BaseballGameInputView.java
new file mode 100644
index 00000000..8147f797
--- /dev/null
+++ b/src/main/java/game/baseball/adapter/in/BaseballGameInputView.java
@@ -0,0 +1,81 @@
+package game.baseball.adapter.in;
+
+import game.baseball.application.port.out.GameInputPort;
+import game.baseball.application.port.in.command.GuessCommand;
+import game.baseball.application.port.in.command.RestartCommand;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class BaseballGameInputView implements GameInputPort {
+    private static final int GUESS_LENGTH = 3;
+    private static final char DIGIT_ZERO = '0';
+    private static final String RESTART_COMMAND = "1";
+    private static final String QUIT_COMMAND = "2";
+
+    private final Scanner scanner = new Scanner(System.in);
+
+    @Override
+    public GuessCommand readGuessCommand() {
+        return new GuessCommand(parseGuess(readLine()));
+    }
+
+    @Override
+    public RestartCommand readRestartCommand() {
+        return new RestartCommand(parseRestart(readLine()));
+    }
+
+    private String readLine() {
+        return scanner.nextLine();
+    }
+
+    private List<Integer> parseGuess(String userInput) {
+        String input = normalize(userInput);
+        validateLength(input);
+        return toDigits(input);
+    }
+
+    private String normalize(String userInput) {
+        if (userInput == null) {
+            throw new IllegalArgumentException("입력값이 null 입니다.");
+        }
+        return userInput.trim();
+    }
+
+    private void validateLength(String input) {
+        if (input.length() != GUESS_LENGTH) {
+            throw new IllegalArgumentException(
+                    String.format("%d자리 숫자를 입력해야 합니다.", GUESS_LENGTH)
+            );
+        }
+    }
+
+    private List<Integer> toDigits(String input) {
+        List<Integer> digits = new ArrayList<>();
+        for (int i = 0; i < input.length(); i++) {
+            digits.add(parseDigit(input.charAt(i)));
+        }
+        return digits;
+    }
+
+    private int parseDigit(char ch) {
+        if (!Character.isDigit(ch)) {
+            throw new IllegalArgumentException("숫자만 입력할 수 있습니다.");
+        }
+        return ch - DIGIT_ZERO;
+    }
+
+    private boolean parseRestart(String command) {
+        String normalized = normalize(command);
+        if (RESTART_COMMAND.equals(normalized)) {
+            return true;
+        }
+        if (QUIT_COMMAND.equals(normalized)) {
+            return false;
+        }
+        throw new IllegalArgumentException(
+                String.format("%s 또는 %s를 입력해야 합니다.", RESTART_COMMAND, QUIT_COMMAND)
+        );
+    }
+}
diff --git a/src/main/java/game/baseball/adapter/in/BaseballGameOutputView.java b/src/main/java/game/baseball/adapter/in/BaseballGameOutputView.java
new file mode 100644
index 00000000..6b2c0a48
--- /dev/null
+++ b/src/main/java/game/baseball/adapter/in/BaseballGameOutputView.java
@@ -0,0 +1,41 @@
+package game.baseball.adapter.in;
+
+import game.baseball.application.port.out.GameOutputPort;
+import game.baseball.domain.Hint;
+
+public class BaseballGameOutputView implements GameOutputPort {
+    private static final int ANSWER_LENGTH = 3;
+    private static final String RESTART_OPTION = "1";
+    private static final String QUIT_OPTION = "2";
+
+    private static final String NUMBER_INPUT_PROMPT = "숫자를 입력해주세요 : ";
+    private static final String CORRECT_MESSAGE =
+            String.format("%d개의 숫자를 모두 맞히셨습니다. 게임 종료", ANSWER_LENGTH);
+    private static final String OPTION_INPUT_PROMPT =
+            String.format("게임을 새로 시작하려면 %s, 종료하려면 %s를 입력하세요.", RESTART_OPTION, QUIT_OPTION);
+
+    @Override
+    public void showGuessPrompt() {
+        System.out.print(NUMBER_INPUT_PROMPT);
+    }
+
+    @Override
+    public void showResult(Hint hint) {
+        System.out.println(hint.message());
+    }
+
+    @Override
+    public void showGameEnd() {
+        System.out.println(CORRECT_MESSAGE);
+    }
+
+    @Override
+    public void showRestartPrompt() {
+        System.out.println(OPTION_INPUT_PROMPT);
+    }
+
+    @Override
+    public void showError(String message) {
+        System.out.println("[ERROR] " + message);
+    }
+}
diff --git a/src/main/java/game/baseball/adapter/out/BaseballPrinter.java b/src/main/java/game/baseball/adapter/out/BaseballPrinter.java
new file mode 100644
index 00000000..f9bd70ee
--- /dev/null
+++ b/src/main/java/game/baseball/adapter/out/BaseballPrinter.java
@@ -0,0 +1,18 @@
+package game.baseball.adapter.out;
+
+import game.GamePrinter;
+
+public class BaseballPrinter implements GamePrinter {
+    private static final String START_MESSAGE = "숫자 야구 게임을 시작합니다.";
+    private static final String END_MESSAGE = "게임을 종료합니다.";
+
+    @Override
+    public void printStartingMessage() {
+        System.out.println(START_MESSAGE);
+    }
+
+    @Override
+    public void printEndingMessage() {
+        System.out.println(END_MESSAGE);
+    }
+}
diff --git a/src/main/java/game/baseball/application/BaseballGameService.java b/src/main/java/game/baseball/application/BaseballGameService.java
new file mode 100644
index 00000000..18a2fde5
--- /dev/null
+++ b/src/main/java/game/baseball/application/BaseballGameService.java
@@ -0,0 +1,36 @@
+package game.baseball.application;
+
+import game.baseball.application.port.in.BaseballGameUseCase;
+import game.baseball.application.port.in.command.GuessCommand;
+import game.baseball.application.port.out.NumberGeneratorPort;
+import game.baseball.domain.BaseballGame;
+import game.baseball.domain.BaseballNumbers;
+import game.baseball.domain.Hint;
+
+public class BaseballGameService implements BaseballGameUseCase {
+    private final NumberGeneratorPort numberGeneratorPort;
+    private BaseballGame game;
+
+    public BaseballGameService(NumberGeneratorPort numberGeneratorPort) {
+        this.numberGeneratorPort = numberGeneratorPort;
+    }
+
+    @Override
+    public void startNewGame() {
+        BaseballNumbers answer = BaseballNumbers.from(numberGeneratorPort.generate());
+        this.game = new BaseballGame(answer);
+    }
+
+    @Override
+    public Hint guess(GuessCommand command) {
+        ensureGameStarted();
+        BaseballNumbers guess = BaseballNumbers.from(command.digits());
+        return game.guess(guess);
+    }
+
+    private void ensureGameStarted() {
+        if (game == null) {
+            throw new IllegalStateException("게임이 시작되지 않았습니다.");
+        }
+    }
+}
diff --git a/src/main/java/game/baseball/application/port/in/BaseballGameUseCase.java b/src/main/java/game/baseball/application/port/in/BaseballGameUseCase.java
new file mode 100644
index 00000000..481500a1
--- /dev/null
+++ b/src/main/java/game/baseball/application/port/in/BaseballGameUseCase.java
@@ -0,0 +1,10 @@
+package game.baseball.application.port.in;
+
+import game.baseball.application.port.in.command.GuessCommand;
+import game.baseball.domain.Hint;
+
+public interface BaseballGameUseCase {
+    void startNewGame();
+
+    Hint guess(GuessCommand command);
+}
diff --git a/src/main/java/game/baseball/application/port/in/command/GuessCommand.java b/src/main/java/game/baseball/application/port/in/command/GuessCommand.java
new file mode 100644
index 00000000..f66c6d0b
--- /dev/null
+++ b/src/main/java/game/baseball/application/port/in/command/GuessCommand.java
@@ -0,0 +1,9 @@
+package game.baseball.application.port.in.command;
+
+import java.util.List;
+
+public record GuessCommand(List<Integer> digits) {
+    public GuessCommand {
+        digits = List.copyOf(digits);
+    }
+}
diff --git a/src/main/java/game/baseball/application/port/in/command/RestartCommand.java b/src/main/java/game/baseball/application/port/in/command/RestartCommand.java
new file mode 100644
index 00000000..331936c3
--- /dev/null
+++ b/src/main/java/game/baseball/application/port/in/command/RestartCommand.java
@@ -0,0 +1,4 @@
+package game.baseball.application.port.in.command;
+
+public record RestartCommand(boolean restart) {
+}
diff --git a/src/main/java/game/baseball/application/port/out/GameInputPort.java b/src/main/java/game/baseball/application/port/out/GameInputPort.java
new file mode 100644
index 00000000..4ed10114
--- /dev/null
+++ b/src/main/java/game/baseball/application/port/out/GameInputPort.java
@@ -0,0 +1,10 @@
+package game.baseball.application.port.out;
+
+import game.baseball.application.port.in.command.GuessCommand;
+import game.baseball.application.port.in.command.RestartCommand;
+
+public interface GameInputPort {
+    GuessCommand readGuessCommand();
+
+    RestartCommand readRestartCommand();
+}
diff --git a/src/main/java/game/baseball/application/port/out/GameOutputPort.java b/src/main/java/game/baseball/application/port/out/GameOutputPort.java
new file mode 100644
index 00000000..745ddf4f
--- /dev/null
+++ b/src/main/java/game/baseball/application/port/out/GameOutputPort.java
@@ -0,0 +1,15 @@
+package game.baseball.application.port.out;
+
+import game.baseball.domain.Hint;
+
+public interface GameOutputPort {
+    void showGuessPrompt();
+
+    void showResult(Hint hint);
+
+    void showGameEnd();
+
+    void showRestartPrompt();
+
+    void showError(String message);
+}
diff --git a/src/main/java/game/baseball/application/port/out/NumberGeneratorPort.java b/src/main/java/game/baseball/application/port/out/NumberGeneratorPort.java
new file mode 100644
index 00000000..f5550b2c
--- /dev/null
+++ b/src/main/java/game/baseball/application/port/out/NumberGeneratorPort.java
@@ -0,0 +1,7 @@
+package game.baseball.application.port.out;
+
+import java.util.List;
+
+public interface NumberGeneratorPort {
+    List<Integer> generate();
+}
diff --git a/src/main/java/game/baseball/config/BaseballGameConfig.java b/src/main/java/game/baseball/config/BaseballGameConfig.java
new file mode 100644
index 00000000..7fb30495
--- /dev/null
+++ b/src/main/java/game/baseball/config/BaseballGameConfig.java
@@ -0,0 +1,31 @@
+package game.baseball.config;
+
+import game.GamePrinter;
+import game.GameRunner;
+import game.GamingConsole;
+import game.baseball.adapter.RandomNumberGenerator;
+import game.baseball.adapter.in.BaseballGameController;
+import game.baseball.adapter.in.BaseballGameInputView;
+import game.baseball.adapter.in.BaseballGameOutputView;
+import game.baseball.adapter.out.BaseballPrinter;
+import game.baseball.application.BaseballGameService;
+import game.baseball.application.port.in.BaseballGameUseCase;
+import game.baseball.application.port.out.GameInputPort;
+import game.baseball.application.port.out.GameOutputPort;
+import game.baseball.application.port.out.NumberGeneratorPort;
+
+public class BaseballGameConfig {
+    public GameRunner gameRunner() {
+        NumberGeneratorPort numberGeneratorPort = new RandomNumberGenerator();
+        GameInputPort inputPort = new BaseballGameInputView();
+        GameOutputPort outputPort = new BaseballGameOutputView();
+        BaseballGameUseCase useCase = new BaseballGameService(numberGeneratorPort);
+        GamingConsole console = new BaseballGameController(
+                useCase,
+                inputPort,
+                outputPort
+        );
+        GamePrinter printer = new BaseballPrinter();
+        return new GameRunner(console, printer);
+    }
+}
diff --git a/src/main/java/game/baseball/domain/BaseballGame.java b/src/main/java/game/baseball/domain/BaseballGame.java
new file mode 100644
index 00000000..770ebeec
--- /dev/null
+++ b/src/main/java/game/baseball/domain/BaseballGame.java
@@ -0,0 +1,15 @@
+package game.baseball.domain;
+
+public class BaseballGame {
+    private final BaseballNumbers answer;
+
+    public BaseballGame(BaseballNumbers answer) {
+        this.answer = answer;
+    }
+
+    public Hint guess(BaseballNumbers guess) {
+        int strike = answer.countStrike(guess);
+        int ball = answer.countBall(guess);
+        return Hint.of(strike, ball);
+    }
+}
diff --git a/src/main/java/game/baseball/domain/BaseballNumber.java b/src/main/java/game/baseball/domain/BaseballNumber.java
new file mode 100644
index 00000000..57173db7
--- /dev/null
+++ b/src/main/java/game/baseball/domain/BaseballNumber.java
@@ -0,0 +1,44 @@
+package game.baseball.domain;
+
+public class BaseballNumber {
+    private static final int MIN_NUMBER = 1;
+    private static final int MAX_NUMBER = 9;
+
+    private final Integer number;
+
+    private BaseballNumber(Integer number) {
+        this.number = number;
+    }
+
+    public static BaseballNumber of(Integer number) {
+        validate(number);
+        return new BaseballNumber(number);
+    }
+
+    private static void validate(final Integer number) {
+        if (number < MIN_NUMBER || number > MAX_NUMBER) {
+            throw new IllegalArgumentException(
+                    String.format("야구 숫자의 범위는 %d에서 %d까지의 자연수 입니다.", MIN_NUMBER, MAX_NUMBER)
+            );
+        }
+    }
+
+    public int value() {
+        return number;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof BaseballNumber val)) {
+            return false;
+        }
+        return number.equals(val.number);
+    }
+
+    @Override
+    public int hashCode() {
+        return number.hashCode();
+    }
+
+}
diff --git a/src/main/java/game/baseball/domain/BaseballNumbers.java b/src/main/java/game/baseball/domain/BaseballNumbers.java
new file mode 100644
index 00000000..513aad4c
--- /dev/null
+++ b/src/main/java/game/baseball/domain/BaseballNumbers.java
@@ -0,0 +1,87 @@
+package game.baseball.domain;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class BaseballNumbers {
+    private static final int NUMBERS_SIZE = 3;
+
+    private final List<BaseballNumber> numbers;
+
+    private BaseballNumbers(List<BaseballNumber> numbers) {
+        this.numbers = List.copyOf(numbers);
+    }
+
+    public static BaseballNumbers from(final List<Integer> numbers) {
+        validate(numbers);
+        return new BaseballNumbers(createBaseballNumbers(numbers));
+    }
+
+    private static void validate(final List<Integer> numbers) {
+        validateNotNull(numbers);
+        validateSize(numbers);
+        validateDistinct(numbers);
+    }
+
+    private static void validateNotNull(List<Integer> numbers) {
+        if (numbers == null) {
+            throw new IllegalArgumentException("숫자 목록이 null 입니다.");
+        }
+    }
+
+    private static void validateSize(final List<Integer> numbers) {
+        if (numbers.size() != NUMBERS_SIZE) {
+            throw new IllegalArgumentException(
+                    String.format("숫자야구의 숫자 개수는 %d개입니다.", NUMBERS_SIZE)
+            );
+        }
+    }
+
+    private static void validateDistinct(final List<Integer> numbers) {
+        Set<Integer> unique = new HashSet<>();
+        for (Integer number : numbers) {
+            if (unique.contains(number)) {
+                throw new IllegalArgumentException("숫자는 서로 중복될 수 없습니다.");
+            }
+            unique.add(number);
+        }
+    }
+
+    private static List<BaseballNumber> createBaseballNumbers(List<Integer> numbers) {
+        List<BaseballNumber> baseballNumbers = new ArrayList<>();
+        for (Integer number : numbers) {
+            baseballNumbers.add(BaseballNumber.of(number));
+        }
+        return baseballNumbers;
+    }
+
+    public int countStrike(BaseballNumbers guess) {
+        int strike = 0;
+        for (int i = 0; i < numbers.size(); i++) {
+            if (numbers.get(i).equals(guess.numbers.get(i))) {
+                strike++;
+            }
+        }
+        return strike;
+    }
+
+    public int countBall(BaseballNumbers guess) {
+        int ball = 0;
+        for (int i = 0; i < numbers.size(); i++) {
+            BaseballNumber candidate = guess.numbers.get(i);
+            if (isStrikePosition(candidate, i)) {
+                continue;
+            }
+            if (numbers.contains(candidate)) {
+                ball++;
+            }
+        }
+        return ball;
+    }
+
+    private boolean isStrikePosition(BaseballNumber candidate, int index) {
+        return numbers.get(index).equals(candidate);
+    }
+}
diff --git a/src/main/java/game/baseball/domain/Hint.java b/src/main/java/game/baseball/domain/Hint.java
new file mode 100644
index 00000000..866671d2
--- /dev/null
+++ b/src/main/java/game/baseball/domain/Hint.java
@@ -0,0 +1,77 @@
+package game.baseball.domain;
+
+public class Hint {
+    private static final int MIN_COUNT = 0;
+    private static final int MAX_COUNT = 3;
+    private static final int SOLVED_STRIKE_COUNT = 3;
+
+    private final int strike;
+    private final int ball;
+
+    private Hint(int strike, int ball) {
+        this.strike = strike;
+        this.ball = ball;
+    }
+
+    public static Hint of(int strike, int ball) {
+        validate(strike, ball);
+        return new Hint(strike, ball);
+    }
+
+    public boolean isSolved() {
+        return strike == SOLVED_STRIKE_COUNT;
+    }
+
+    public String message() {
+        if (isNothing()) {
+            return "낫싱";
+        }
+        return buildMessage();
+    }
+
+    private boolean isNothing() {
+        return strike == MIN_COUNT && ball == MIN_COUNT;
+    }
+
+    private String buildMessage() {
+        StringBuilder sb = new StringBuilder();
+        appendStrike(sb);
+        appendBall(sb);
+        return sb.toString();
+    }
+
+    private void appendStrike(StringBuilder sb) {
+        if (strike == MIN_COUNT) {
+            return;
+        }
+        sb.append(strike).append("스트라이크");
+    }
+
+    private void appendBall(StringBuilder sb) {
+        if (ball == MIN_COUNT) {
+            return;
+        }
+        if (!sb.isEmpty()) {
+            sb.append(" ");
+        }
+        sb.append(ball).append("볼");
+    }
+
+    private static void validate(int strike, int ball) {
+        if (strike < MIN_COUNT || strike > MAX_COUNT) {
+            throw new IllegalArgumentException(
+                    String.format("스트라이크는 %d~%d 범위여야 합니다.", MIN_COUNT, MAX_COUNT)
+            );
+        }
+        if (ball < MIN_COUNT || ball > MAX_COUNT) {
+            throw new IllegalArgumentException(
+                    String.format("볼은 %d~%d 범위여야 합니다.", MIN_COUNT, MAX_COUNT)
+            );
+        }
+        if (strike + ball > MAX_COUNT) {
+            throw new IllegalArgumentException(
+                    String.format("스트라이크와 볼의 합은 %d을 초과할 수 없습니다.", MAX_COUNT)
+            );
+        }
+    }
+}
diff --git a/src/test/java/game/baseball/domain/BaseballGameTest.java b/src/test/java/game/baseball/domain/BaseballGameTest.java
new file mode 100644
index 00000000..2904ae3f
--- /dev/null
+++ b/src/test/java/game/baseball/domain/BaseballGameTest.java
@@ -0,0 +1,38 @@
+package game.baseball.domain;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class BaseballGameTest {
+
+    @Test
+    void guessAllStrike() {
+        BaseballGame game = new BaseballGame(BaseballNumbers.from(List.of(1, 2, 3)));
+
+        Hint hint = game.guess(BaseballNumbers.from(List.of(1, 2, 3)));
+
+        assertThat(hint.isSolved()).isTrue();
+        assertThat(hint.message()).isEqualTo("3스트라이크");
+    }
+
+    @Test
+    void guessStrikeAndBall() {
+        BaseballGame game = new BaseballGame(BaseballNumbers.from(List.of(1, 2, 3)));
+
+        Hint hint = game.guess(BaseballNumbers.from(List.of(1, 3, 2)));
+
+        assertThat(hint.message()).isEqualTo("1스트라이크 2볼");
+    }
+
+    @Test
+    void guessNothing() {
+        BaseballGame game = new BaseballGame(BaseballNumbers.from(List.of(1, 2, 3)));
+
+        Hint hint = game.guess(BaseballNumbers.from(List.of(4, 5, 6)));
+
+        assertThat(hint.message()).isEqualTo("낫싱");
+    }
+}
diff --git a/src/test/java/game/baseball/domain/BaseballNumberTest.java b/src/test/java/game/baseball/domain/BaseballNumberTest.java
new file mode 100644
index 00000000..917a8cd0
--- /dev/null
+++ b/src/test/java/game/baseball/domain/BaseballNumberTest.java
@@ -0,0 +1,28 @@
+package game.baseball.domain;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class BaseballNumberTest {
+
+    @Test
+    void createWithValidRange() {
+        BaseballNumber number = BaseballNumber.of(1);
+
+        assertThat(number.value()).isEqualTo(1);
+    }
+
+    @Test
+    void rejectNumberLessThanOne() {
+        assertThatThrownBy(() -> BaseballNumber.of(0))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void rejectNumberGreaterThanNine() {
+        assertThatThrownBy(() -> BaseballNumber.of(10))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+}
diff --git a/src/test/java/game/baseball/domain/BaseballNumbersTest.java b/src/test/java/game/baseball/domain/BaseballNumbersTest.java
new file mode 100644
index 00000000..c28d127f
--- /dev/null
+++ b/src/test/java/game/baseball/domain/BaseballNumbersTest.java
@@ -0,0 +1,45 @@
+package game.baseball.domain;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class BaseballNumbersTest {
+
+    @Test
+    void createWithValidNumbers() {
+        BaseballNumbers numbers = BaseballNumbers.from(List.of(1, 2, 3));
+
+        assertThat(numbers.countStrike(BaseballNumbers.from(List.of(1, 2, 3)))).isEqualTo(3);
+    }
+
+    @Test
+    void rejectNullList() {
+        assertThatThrownBy(() -> BaseballNumbers.from(null))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void rejectWrongSize() {
+        assertThatThrownBy(() -> BaseballNumbers.from(List.of(1, 2)))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void rejectDuplicateNumbers() {
+        assertThatThrownBy(() -> BaseballNumbers.from(List.of(1, 1, 2)))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void countStrikeAndBall() {
+        BaseballNumbers answer = BaseballNumbers.from(List.of(1, 2, 3));
+        BaseballNumbers guess = BaseballNumbers.from(List.of(1, 3, 2));
+
+        assertThat(answer.countStrike(guess)).isEqualTo(1);
+        assertThat(answer.countBall(guess)).isEqualTo(2);
+    }
+}
diff --git a/src/test/java/game/baseball/domain/HintTest.java b/src/test/java/game/baseball/domain/HintTest.java
new file mode 100644
index 00000000..155ff093
--- /dev/null
+++ b/src/test/java/game/baseball/domain/HintTest.java
@@ -0,0 +1,55 @@
+package game.baseball.domain;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class HintTest {
+
+    @Test
+    void messageWhenNothing() {
+        Hint hint = Hint.of(0, 0);
+
+        assertThat(hint.message()).isEqualTo("낫싱");
+    }
+
+    @Test
+    void messageWhenStrikeAndBall() {
+        Hint hint = Hint.of(1, 2);
+
+        assertThat(hint.message()).isEqualTo("1스트라이크 2볼");
+    }
+
+    @Test
+    void messageWhenOnlyBall() {
+        Hint hint = Hint.of(0, 2);
+
+        assertThat(hint.message()).isEqualTo("2볼");
+    }
+
+    @Test
+    void solvedWhenThreeStrike() {
+        Hint hint = Hint.of(3, 0);
+
+        assertThat(hint.isSolved()).isTrue();
+    }
+
+    @Test
+    void rejectInvalidStrikeRange() {
+        assertThatThrownBy(() -> Hint.of(4, 0))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void rejectInvalidBallRange() {
+        assertThatThrownBy(() -> Hint.of(0, 4))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+
+    @Test
+    void rejectSumGreaterThanThree() {
+        assertThatThrownBy(() -> Hint.of(2, 2))
+                .isInstanceOf(IllegalArgumentException.class);
+    }
+}